1. Field of the Invention
The present invention relates to a method for selecting a broadcasting tower, a program for selecting the broadcasting tower, a storage medium storing same program and a broadcast receiving device, and more particularly to the method for selecting one broadcasting tower out of a plurality of broadcasting towers each being able to transmit together broadcast waves on a plurality of channels being receivable in an area, the program of selecting the broadcasting tower, a storage medium storing same program and the broadcast receiving device to which the above method is applied.
The present application claims priority of Japanese Patent Application No. 2002-129248 filed on Apr. 30, 2002, which is hereby incorporated by reference.
2. Description of the Related Art
A broadcast receiving device receives, through a receiving antenna, broadcast waves transmitted from a broadcasting station or a relay station with a transmitting antenna (hereinafter referred to as a broadcasting station or a like) and, after having performed signal processing an the received broadcast waves, displays a video on its display screen or outputs an amplified audio from a speaker. Therefore, in order for the viewers or a like to watch television, their broadcast receiving devices have to directly receive broadcast waves from the receiving antenna. However, generally, an area in which a receiving antenna can directly receive broadcast waves transmitted from a broadcasting station or a like, those in a VHF (Very High Frequency) band in particular, is limited due to obstructions such as high-rise buildings, mountains, or a like, or due to a difference in magnitude of outputs of broadcast waves.
Moreover, in recent years, though many local TV (television) broadcasting stations and/or local FM (Frequency Modulation) stations (hereinafter, collectively called “local broadcasting stations”) providing specially interesting broadcasts for residents in each of areas have been set up, however, due to various conditions of purposes of their establishment, their management sizes or a like, outputs of broadcast waves are not so high. Furthermore, the local TV broadcasting station generally gives broadcasts using broadcast waves in a UHF (Ultra High Frequency) band, however, an area in which broadcast waves in the UHF band can be directly received through the receiving antenna is narrower than that in which broadcast waves in the VHF band can be directly received through the receiving antenna.
To solve this problem, in an area in which direct receipt of broadcast waves is difficult (hereinafter referred to a “broadcast wave hard-to-receive area”) or in an area in which many local broadcasting stations are set up, a tower (hereinafter referred to a “broadcasting tower”) is conventionally placed which is equipped with a transmitting antenna being able to transmit together broadcast waves on a plurality of broadcasting stations including broadcast waves in the UHF band obtained by conversion of broadcast waves in the VHF band. Hereinafter, a group of channels of broadcasting stations for broadcast waves being transmitted by each of broadcasting towers is called “a channel group”. Therefore, in the case of buying a new broadcast receiving device or of movement into the area in which receipt of broadcast waves is difficult, the viewers or a like have to operate the broadcast receiving device so as to automatically select a channel for broadcast waves that can be received in the area.
Next, a conventional method for selecting the broadcasting tower in a TV receiver (television broadcast receiving device) is described below. It is presumed in descriptions below that the receiving antenna installed on a roof of a detached house, a collective house such as an apartment house or a like, is directed toward a broadcasting tower existing in a direction in which broadcast waves providing most excellent video quality or sound quality can be received. It is also presumed that, in an area in which many broadcasting towers are set up, the viewers or a like cannot easily get information about which broadcasting tower a receiving antenna is directed toward. Such the area is, for example, a western region of Kanagawa Prefecture (JAPAN). FIG. 9 is a diagram showing names of places in which broadcasting towers are set up in the western region of Kanagawa Prefecture and in regions surrounding the western region and channels of TV broadcasting stations transmitting broadcast waves from each of the broadcasting towers and commonly called names of the TV broadcasting stations. The channel includes a first channel (in a VHF band) to a sixty-second channel (in a UHF band). Moreover, lower numbers are assigned to each of the channel groups shown in FIG. 9 containing more lower-numbered channels out of the channels from the first channel to sixty-second channel. That is, a broadcasting tower “Tokyo” is a first channel group, a broadcasting tower “Hatano” is a second channel group, a broadcasting tower “Ashigara” is a third channel group, a broadcasting tower “Yugawara” is a fourth channel group, and a broadcasting tower “Odawara” is a fifth channel group. Such the information as shown in FIG. 9 is periodically made public by publications or a like.
First, configurations of the conventional TV receiver are described by referring to FIG. 10. The conventional TV receiver shown in FIG. 10, which is to be connected to a receiving antenna 1, includes a tuner 2, a broadcasting station existence judging section 3, a video/audio processing section 4, a display section 5, a audio outputting section 6, a control section 7, a program storing section 8, a known tower information storing section 9, a receiving broadcasting station storing section 10, and an operation section 11. The tuner 2 converts broadcast signals on a first channel to a sixty-twenty channel which have been received and already converted by the receiving antenna 1, into intermediate frequency signals SM and feeds them to the video/audio processing section 4 and, at a same time, detects a wave checking signal RWD to be used for judging existence of broadcast waves given by a broadcasting station from the broadcast signals and feeds it to the broadcasting station existence judging section 3. The broadcasting station existence judging section 3, based on the wave checking signal RWD fed from the tuner 2, detects a channel over which telecasting broadcasts are given and feeds a detected result DR to the control section 7. The video/audio processing section 4 performs signal processing on the intermediate frequency signal SM fed from the tuner 2 to produce a video signal SP and a audio signal SA and feeds the video signal SP to the display section 5 and feeds the audio signal SA to the audio outputting section 6. The display section 5 has a display unit such as a CRT (Cathode Ray Tube) display unit, a liquid crystal display unit, a plasma display unit, or a like (not shown) and, based on the video signal SP fed from the video/audio processing section 4, displays a video on the display unit. Moreover, the display section 5, based on a data signal SD fed from the control section 7, displays various information including a channel that can be received, a broadcasting tower, an instruction to a viewer, or a like on the display unit (not shown). The audio outputting section 6 has a speaker (not shown) and, based on the audio signal SA fed from the video/audio processing section 4, outputs an amplified audio.
The control section 7 is made up of a CPU (Central Processing Unit) or a like (not shown) and executes a program read from the program storing section 8 to control each of components. For example, the control section 7, based on the detected result DR fed from the broadcasting station existence judging section 3, selects a broadcasting tower from which broadcast waves can be received and lets the tuner 2 receive a plurality of broadcast waves transmitted from the selected broadcasting tower. The program storing section 8 is made up of a semiconductor memory such as a ROM (Read only Memory), RAM (Random Access Memory), flash memory, or a like (not shown) and stores, in advance, various types of program to be executed by the control section 7. The known tower information storing section 9 is made up of a semiconductor memory such as the ROM, RAM, flash memory, or a like (not shown) and stores, in advance, information about all broadcasting towers existing across Japan. The broadcasting tower information includes information about types of broadcast wave given by a broadcasting station that each of the broadcasting towers can transmit, that is, information about the channel group described above. The receiving broadcasting station storing section 10 is made up of a semiconductor memory such as the RAM, flash memory, or a like (not shown) and stores a wave receivable channel table 10a described later (see FIG. 13), information about broadcasting towers or channels that can provide an excellent state of receiving broadcast waves. The operation section 11 has a power switch, volume adjusting key, channel switching keys, various types of function key, a receiving unit to receive a light signal or a wave transmitted from a remote controller (all not shown). The operation section 11 feeds, when various keys or remote controller (not shown) are manipulated by the viewer, a signal corresponding to a type of the manipulated key or to a kind of light signal produced by the manipulation and to time for pressing down the keys or a like, to the control section 7.
Next, a method for selecting the broadcasting tower in the conventional TV receiver having configurations described above is explained below. The viewer, after having connected the conventional TV receiver to the receiving antenna 1, provides power to the TV receiver. Then, the viewer, after having manipulated the operation section 11 or the remote controller (not shown) to set the TV receiver to an automatic channel selection mode, selects “Kanagawa” being his/her resident place. This causes the control section 7 to start automatic channel selecting operation according to a flowchart shown in FIG. 11. That is, the control section 7 first makes its routine proceed to Step SP1 and, after having set a channel flag CH to “1” as an initial value in order to check whether or not broadcast waves on the first channel can be received, to Step SP2.
In Step SP2; the control section 7, based on the detected result DR fed from the broadcasting station existence judging section 3, checks whether or not the broadcasting station existence judging section 3 has judged a broadcasting station corresponding to the targeted channel flag CH to exist. The broadcasting station existence judging section 3, by using a method described below, judges whether or not the broadcasting station exists. The wave checking signal RWD to be fed from the tuner 2 has such a waveform as shown in FIG. 12. Therefore, even if a central frequency of a broadcast wave on a channel is at a specified voltage V0, if the receiving antenna 1 is placed apart even a bit from a broadcasting tower, since an amplitude H becomes extremely small, measurement at a sensitivity level is made impossible and the existence of a broadcasting station cannot be judged based on the sensitivity level. Conventionally, whether or not a broadcasting station corresponding to the channel exist is judged by whether, at a frequency being about a central frequency of the broadcast wave, a waveform of the wave checking signal RWD is at an S-shaped curve being symmetric with respect to the central frequency. As shown in FIG. 12, the waveform of the wave checking signal RWD is at an S-shaped curve being symmetric with respect to a central frequency for a first channel f1 and to a central frequency for a third channel f3, however, the waveform of the wave checking signal RWD is not at the S-shaped curve being symmetric with respect to a central frequency for a second channel f2. Therefore, the waveform of the wave checking signal RWD shows that broadcasting stations corresponding to the first and third channels exist however, a broadcasting station corresponding to the second channel does not exist
If a YES answer is obtained as a result from the judgement in Step SP2, that is, if a broadcasting station corresponding to. a targeted channel flag CH is judged to exist, the control section 7 makes its routine proceed to Step SP3. In this example, as is apparent from FIG. 12, since the waveform of the wave checking signal RWD shows that the channel flag CH is “1”, that is, the broadcasting station corresponding to the first channel exists, the control section 7 makes its routine proceed to Step SP3. In Step SP3, the control section 7, after having set a detection flag DF for a targeted channel flag CH presented in a wave receivable channel table 10a stored in the receiving broadcasting station storing section 10 to “1”, makes its routine proceed to Step SP5. Here, the wave receivable channel table 10a is a table showing a state in which either of “1” or “0” is set to each of the channels including a first to sixty-second channel. Moreover, a detection flag DF for a channel is set to “1” when a broadcasting station corresponding to the channel is judged to exist in Step SP1 and to “0” when the broadcasting station corresponding to the channel is judged not to exist. In this example, since the broadcasting station corresponding to the first channel has been judged to exist, the control section 7, after having set the detection flag DF for the first channel to “1”, makes its routine proceed to Step SP5. On the other hand, if a NO answer is obtained as a result from the judgement in Step SP2, that is, if the broadcasting station corresponding to the channel flag CH is judged not to exist, the control section 7 makes its routine proceed to Step SP4.
In Step SP4, the control section 7, after having set the detection flag DF for the channel flag CH presented in the wave receivable channel table 10a to “0”, makes its routine proceed to Step SP5.
In Step SP5, the control section 7 judges whether or not the channel flag CH is “62”. If a NO answer is obtained at a result from the judgement, the control section 7 makes its routine proceed to Step SP6. In this case, since the channel flag CH is “1” and is not “62”, the control section 7 makes its routine proceed to Step SP6.
In Step SP6, the control section 7, having incremented each of values of all the channel flags CH by 1, makes its routine return to Step SP2 and repeats the above processes in Step SP2 to SP4. Then, when the channel flag CH is changed to be “62”, a YES answer is obtained in Step SP5 and the control section 7 makes its routine proceed to Step SP7. Thus, by repetition of the processes in Step SP2 to Step SP4 described above, each of the detection flags DF for each of the channels presented in the wave receivable channel table 10a is set to “1” or “0” as shown in FIG. 13.
In Step SP7, the control section 7, after having set a channel group flag CG to “1” as an initial value in order to check whether or not broadcast waves on all the channels belonging to the first channel group (broadcasting channel tower “Tokyo”) can be received, makes its routine proceed to Step SP8. In Step SF8, the control section 7 judges whether or not broadcast waves on all the channels belonging to the channel group of the channel group flag CG can be received by referring to information about known towers existing in an area selected by the viewer and existing in its surrounding area out of information about the known towers set up in all parts of Japan being stored in the known tower information storing section 9 and to the wave receivable channel table 10a being stored in the receiving broadcasting station storing section 10. If a NO answer is obtained as a result from the judgement, the control section 7 makes its routine proceed to Step SP9. In the example, as is apparent from comparison between information about broadcasting towers set up in the western region of “Kanagawa” and in regions surrounding the western region of “Kanagawa” shown in FIG. 9 and information provided by the wave receivable channel table 10a shown in FIG. 13, though each of the detection flags DF for the first, third, eighth, twelfth, sixteenth channels belonging to the first channel group (broadcasting channel tower “Tokyo”) is set to “1”, each of the detection flags DF for the fourth, sixth, tenth, or fourteenth channels belonging to the first channel group (broadcasting channel tower “Tokyo”) is set to “0”. Therefore, the control section 7 makes its routine proceed to Step SP9.
In Step SP9, the control section 7, having incremented the values of the channel group flag CG by 1 in order to check whether or not broadcast waves on all the channels belonging to the second channel group (broadcasting channel tower “Hatano”) can be received, makes its routine return to Step SP8 and then repeats the above process in Step SP8. When broadcast waves on all channels belonging to the second channel group indicated by the channel group flag CG are judged to be able to received by referring to the known tower information (see FIG. 9) and the wave receivable channel table 10a (see FIG. 13), a result from the judgement in Step SP8 becomes a YES answer, and the control section 7 makes its routine proceed to Step SP 10. In the example, as is apparent from comparison between the above tables in FIGS. 9 and 13, since each of the detection flags DF of all channels belonging to the second channel group (broadcasting tower “Hatano”) is set to “1”, if a value of the channel group flag CG is “2”, the control section 7 makes its routine proceed to Step SP 10. In Step SP 10, the control section 7, after having registered a broadcasting tower which possesses the channel group corresponding to a value of the targeted channel group flag CG, as an effective broadcasting tower, on the receiving broadcasting storing section 10, terminates a series of the related processes. Therefore, in this example, the control section 7 registers the broadcasting tower “Hatano”, as an effective broadcasting tower, on the receiving broadcast storing section 10.
However, in the conventional method for selecting a broadcasting station, since channel groups are compared in ascending order of its number in the waver receivable channel table 10a in the processes in Step SP7 to SP10, in spite of a fact that a viewer lives in Odawara city and that the broadcasting station “Odawara” is placed in the Odawara city, since the broadcasting tower “Hatano” is the second channel group and the broadcasting tower “Odawara” is the fifth channel group, the control section 7 registers the broadcasting tower “Hatano” being set up in Hatano city being positioned far from the Odawara city as an effective broadcasting tower on the receiving broadcast storing section 10.
Thus, in the conventional method for selecting a broadcasting tower, in some cases, there is a risk that such a broadcasting station as provides lower video and audio quality is registered as an effective broadcasting tower. In such circumstances, in order to set a broadcasting station that can provide best video and audio quality out of a plurality of broadcasting towers being set up in the area where the viewer lives, the viewer has to change each of the channels one by one, which causes much expense in time and effort. Moreover, in the case of the viewer who cannot change each of the channels one by one, the viewer has to contact an electric goods store or a service company to have the channels changed one by one, which needs much time and costs. Almost the same inconveniences as described above occur in areas in which many local FM broadcasting stations are set up.